Each molecule of ammonium sulphate contains two NH4+ ions and one SO42- ions. It is a mixture of two monatomic nitrogen and hydrogen ions and one polyatomic sulfate ion. For an insoluble combination, write the formula for that compound as a product (solid state). When the cation and/or the anion is a polyatomic ion, parentheses may be used to group the atoms in the ion together to write the formula. For example, the salt ammonium sulfate consists of the cation NH 4 + and the sulfate anion SO 4 2-. Which of the following is true about the compound ammonium sulfate [(NH4)2SO4]? The chemical formula of Mohrs salt is (NH4)2Fe(SO4)2·6H2O. It is a salt of monatomic nitrogen, hydrogen, sulfur, and oxygen ions. It is a mixture of three polyatomic ammonium ions and a polyatomic sulfate ion. "Sulfate" is a polyatomic anion with the formula SO 4 2–. It is a salt of two polyatomic ammonium ions and one polyatomic sulfate ion. In this example, we know ammonium sulfate and barium chloride are soluble. 1. Molecular formula of Mohr's salt? It is a mixture of three polyatomic ammonium ions and a polyatomic sulfate ion. The proper formula here, then, is (NH 4) 2 (SO 4). If we we switch partners, we would have barium sulfate and ammonium chloride. "Ammonium" is a polyatomic ion with the formula NH 4 +. The diffusion coefficients of sulfate, ammonium, and phosphate ions were determined directly in the laboratory by placing two samples of homogenized, anoxic mud from Long Island Sound in contact with one another across a planar interface. It is a mixture of two monatomic nitrogen and hydrogen ions and one polyatomic sulfate ion. The other ions remain in solution, and should also be written on the product side, but as aqueous ions. It is a salt of monatomic nitrogen, hydrogen, sulfur, and oxygen ions. To combine these species into a neutral ionic compound, we need two ammonium ions for every sulfate ion. The formula of the salt is written as (NH 4) 2 SO 4. Ammonium iron(II) sulfate, or Mohr's salt, is the inorganic compound with the formula (NH 4) 2 Fe(SO 4) 2 (H 2 O) 6.Containing two different cations, Fe 2+ and NH 4 +, it is classified as a double salt of ferrous sulfate and ammonium sulfate.It is a common laboratory reagent because it is readily crystallized, and crystals resist oxidation by air.